[guptakumarranjeet150]

Summary

This PR implements comprehensive repository governance, code of conduct, line ending normalization, and developer environment standards across the project.

Addressed Issues

Closes #1655
Closes #1656
Closes #1657
Closes #1658

Changes Made

1. Code of Conduct ([general] Add CODE_OF_CONDUCT.md and link it from CONTRIBUTING.md #1655):
   • Added CODE_OF_CONDUCT.md adopting the Contributor Covenant v2.1 standard with reporting contact.
   • Linked Code of Conduct in CONTRIBUTING.md, README.md, and .github/PULL_REQUEST_TEMPLATE.md.
2. Line Endings Normalization ([general] Add .gitattributes to normalise line endings across Windows and Unix checkouts #1656):
   • Updated .gitattributes to explicitly enforce eol=lf across shell scripts, YAML, Markdown, JSON, and source files (.rs, .ts, .tsx, .js).
   • Retained explicit CRLF preservation for Windows command scripts (.bat, .cmd).
3. EditorConfig & Shared Prettier ([general] Add .editorconfig and a shared Prettier config for backend, frontend and docs #1657):
   • Added root .editorconfig specifying 2-space indentation, UTF-8, and LF line endings.
   • Added root .prettierrc configuration and added format script to frontend/package.json.
4. Node.js Engine Alignment ([general] Pin the Node.js version with .nvmrc and declare engines in each package #1658):
   • Verified .nvmrc and package engines consistency (>=22).
   • Documented Node.js 22 requirements in docs/LOCAL_DEVELOPMENT_QUICKSTART.md.